Food-borne botulism in Alaska, 1947-1985: epidemiology and clinical findings.

We reviewed records of all food-borne outbreaks of botulism in Alaska from 1947 through 1985. Fifty-nine confirmed or suspected outbreaks with 156 cases were reported. All outbreaks occurred in Alaska Natives and were associated with eating traditional Alaska Native foods. Forty-four (75%) of the outbreaks were laboratory confirmed and involved 133 persons. The overall annual incidence of confirmed or suspected botulism was 8.6 cases per 100,000 population. Seventeen persons died, an overall case-fatality rate of 11%. Type E toxin accounted for 32 (73%) laboratory-confirmed outbreaks; type A, six (14%); and type B, five (11%). Forty-one cases demonstrated botulinal toxin in one or more specimens (serum, gastric contents, or stool). Of the 41 botulinal toxin-positive persons, 38 (93%) had at least three of the commonly recognized pentad of signs or symptoms--nausea and vomiting, dysphagia, diplopia, dilated and fixed pupils, or dry mouth and throat--and 20 (49%) required respiratory assistance.